Table heading multicolumn problem

Question

I have the following code, which needs 2 sub-columns in the last main column. I have written code as follows:

\begin{table}
  \centering
    \begin{tabular}{|c|l|c|c|}
    \hline
    \multicolumn{1}{|c|}{\bfseries First} & \multicolumn{1}{|c|}{\bfseries Characteristics} & \multicolumn{2}{|c|}{\bfseries Implemented in}\\ A&B \\ \hline
    a & b & c & d \\
    1 & 2 & 3 & 4\\
    \end{tabular}
\end{table}

The result is

I want the "A" and "B" as sub-column within the "Implemented in" column.

Answer 1

You can use \\ && A&B instead of \\ A&B. The first two && are to skip over the first two columns.

Notes:

• As per Bernard'scmment, the multirow package was used to vertically center the first two headers across the two rows.
• As per @AlanMunn's comment, \cline{3-4} can be used to draw lines across specified columns.

---

However, I would strongly recommend you have a look at the booktabs package for tables:

Code:

\documentclass{article}
\usepackage{multirow}

\begin{document}
\begin{tabular}{|c|l|c|c|}
    \hline
    \multirow{2}{*}{\bfseries First} & 
    \multirow{2}{*}{\bfseries Characteristics} & 
    \multicolumn{2}{|c|}{\bfseries Implemented in}\\ \cline{3-4}
    && A&B \\ \hline
    %------
    & b & c & d \\
    1 & 2 & 3 & 4\\
\end{tabular}
\end{document}

Code: booktabs

\documentclass{article}
\usepackage{booktabs}
\usepackage{multirow}

\begin{document}
\begin{tabular}{c l c c}
    \toprule
    \multirow{2}{*}{\bfseries First} & 
    \multirow{2}{*}{\bfseries Characteristics} & 
    \multicolumn{2}{c}{\bfseries Implemented in}\\ \cmidrule(lr){3-4}
    && A&B \\ \cmidrule(lr){1-4}
    %------
    & b & c & d \\
    1 & 2 & 3 & 4\\
    \bottomrule
\end{tabular}
\end{document}

Answer 2

With new package tabularray is simple. Using it you need to insert one ampersand for each column, i.e. in your case three ampersands per row:

\documentclass{article}
\usepackage{tabularray}
\UseTblrLibrary{booktabs}

\begin{document}
\begin{table}[ht]
     \centering
\begin{tblr}{vlines,
             colspec={c l Q[c,wd=3.3em] Q[c,wd=3.3em]},
             row{1}={font=\bfseries},
             }
    \toprule
\SetCell[r=2]{c} First   
    &   \SetCell[r=2]{c} Characteristics 
        &  \SetCell[c=2]{c} Implemented in 
            &       \\
    \midrule
    &   & A & B     \\ 
    \midrule
    & b & c & d     \\
 1  & 2 & 3 & 4     \\
    \bottomrule
    \end{tblr}
\end{table}
\end{document}